Distributed photovoltaic new energy section cooperative control method and system

Abstract

The invention discloses a distributed photovoltaic-containing new energy section cooperative control method and system, and the method is characterized in that the method comprises the following steps: generating a section electricity abandoning target when the section power flow reaches a first threshold, and distributing the electricity abandoning amount to all new energy stations under the section according to the section electricity abandoning target; when the cross-section power flow reaches a second threshold, generating a cross-section electricity limit removal target, and distributing electricity limit removal quantity to all the new energy stations under the cross section according to the cross-section electricity limit removal target; and controlling the new energy station according to the abandoned electric quantity and the released limited electric quantity so as to realize new energy section cooperative control.

Description

Technical Field

[0001] The present invention relates to the field of power systems, and more specifically, to a method and system for coordinated control of new energy sections including distributed photovoltaics. Background Art

[0002] In recent years, with the rapid development of new energy and major changes in the power structure, traditional automatic power generation control has expanded the functions of new energy power generation automatic control and source-grid-load-storage coordinated control. With the large-scale access of new energy, the structure and operation characteristics of the power grid have changed significantly, and the coordination difficulty between power grids in different regions has increased. The method of relying on traditional resources on the main grid side to control the active power of the power grid section cannot meet the power control requirements of the new power system. It is necessary to establish a more complete power grid coordination mechanism, integrate relatively dispersed and volatile distributed resources to participate in the active power control of the main grid section, strengthen the interconnection and coordinated control of cross-regional power grids, and realize the optimal configuration and section control of new energy resources in a larger range.

[0003] With the large-scale access of distributed renewable energy, the power flow distribution in the power grid has become more complex. Traditional power grid section control mainly relies on the regulation of centralized power sources, but the output of distributed renewable energy is intermittent and random, which may cause overload of power flow in some sections. Distributed renewable energy participating in section control can adjust its own output according to the real-time power grid operation status, thereby alleviating the pressure of section power flow and reducing the risk of power grid operation. However, due to the low tracking rate of renewable energy and the small scale of energy storage, renewable energy does not yet have the ability to participate in power grid frequency regulation control. Considering the safety constraints of renewable energy access to the grid, it participates in power grid peak regulation control. In addition, with the further improvement of the controllable capacity of low-voltage distributed photovoltaics, the increase of local controllable resources is also developing towards provincial and local coordinated control. Provincial dispatching has the ability to comprehensively consider various types of adjustable resources and uniformly dispatch based on constraints such as power grid safety constraints and the lowest call cost. However, there is still no global dispatching of sections by aggregating low-voltage distributed photovoltaics in provincial dispatching.

[0004] In view of the above problems, there is an urgent need for a new energy section coordinated control method and system including distributed photovoltaics. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a method and system for coordinated control of new energy sections containing distributed photovoltaics, which optimizes the calculation of the scheduling and control requirements of controllable resources with real-time scheduling characteristics in the entire network or in different regions, and considers the low-voltage distributed photovoltaics as a virtual aggregated control new energy station through aggregation, and participates in the global optimization control strategy of the section.

[0006] The present invention adopts the following technical solution.

[0007] A first aspect of the present invention relates to a method for coordinated control of a new energy section containing distributed photovoltaics, the method comprising the following steps: when the section flow reaches a first threshold, a section power abandonment target is generated, and the amount of abandoned power is distributed to all new energy stations under the section according to the section power abandonment target; when the section flow reaches a second threshold, a section power restriction release target is generated, and the amount of released power restriction is distributed to all new energy stations under the section according to the section power restriction release target; the new energy stations are controlled according to the amount of abandoned power and the amount of released power restriction to achieve coordinated control of new energy sections.

[0008] Preferably, when the section power flow reaches the first threshold, a section power abandonment target is generated, and the power abandonment amount is allocated to all new energy stations under the section according to the section power abandonment target; the section power abandonment target ΔP D for:

[0009] ΔP D =P D -0.9P D.N

[0010] Where P D is the current flow of the section, P D.N is the rated flow of the section;

[0011] The amount of abandoned electricity allocated to any new energy station under the section is:

[0012]

[0013] Where P t.i is the current flow of the new energy station ranked i at time t, and n is the number of new energy stations in the section.

[0014] Preferably, when the section power flow reaches the first threshold, a section power abandonment target is generated, and the power abandonment amount is allocated to all new energy stations under the section according to the section power abandonment target, including: if any new energy station in the section fails to respond to the section coordinated control instruction under three consecutive step sizes Δt, the current new energy station is removed from the section, and P is subtracted from the section power abandonment target. t.i , and redistribute the remaining abandoned electricity within the section.

[0015] Preferably, when the section power flow reaches the second threshold, a section power restriction release target is generated, and the power restriction release amount is distributed to all new energy stations under the section according to the section power restriction release target, including: section power restriction release target ΔP H for:

[0016] ΔP H =0.05P D.N

[0017] The amount of electricity released from restrictions allocated to any new energy station under the section is:

[0018]

[0019] Preferably, when the section power flow reaches the second threshold, a section power restriction release target is generated, and the power restriction release amount is distributed to all new energy stations under the section according to the section power restriction release target, including: continuously performing power restriction release at each step length Δt, if at time t, the power flow after power restriction release of any station meets P t.i <P t-1.i +ΔP H.i , it is considered that the station cannot achieve the target of lifting power restrictions, and at time t+1, it is no longer allocated the target of lifting power restrictions; if at any time t, the power flow after lifting power restrictions at any station meets P t.i ≥P t-1.i +ΔP H.i , it is considered that the station has achieved the target of lifting power restriction, and at time t+1, the target of lifting power restriction will continue to be allocated to it.

[0020] Preferably, the new energy station is controlled according to the amount of abandoned power and the lifting of power limit to achieve coordinated control of new energy sections, including: generating a section power limit instruction for each new energy station according to the amount of abandoned power and the lifting of power limit, and judging whether the section power limit instruction at the current time t is the last section power limit instruction; generating a peak-shaving power limit instruction for each new energy station according to the peak-shaving target of the power grid; and selecting a section power limit instruction or a peak-shaving power limit instruction to control the new energy station.

[0021] Preferably, a section power restriction instruction or a peak-shaving power restriction instruction is selected to control the new energy station, including: if the peak-shaving power restriction instruction is greater than the section power restriction instruction that is not the last time, the new energy station is deployed in the peak-shaving power restriction mode; if the section power restriction instruction is greater than the peak-shaving power restriction instruction, the new energy station is deployed in the section power restriction mode; if the peak-shaving power restriction instruction is greater than the last section power restriction instruction, the new energy station is deployed in the peak-shaving power restriction mode. If the peak-shaving power restriction instruction is greater than the last section power restriction instruction, after adjusting the state of the new energy station according to the section power restriction instruction, the new energy station is deployed in the peak-shaving power restriction mode.

[0022] The second aspect of the present invention relates to a new energy section coordinated control system containing distributed photovoltaics using the method in the first aspect of the present invention; the system includes a power abandonment module, a power restriction release module, and a control module; wherein the power abandonment module is used to generate a section power abandonment target when the section flow reaches a first threshold, and distribute the abandoned power to all new energy stations under the section according to the section power abandonment target; the power restriction release module is used to generate a section power restriction release target when the section flow reaches a second threshold, and distribute the released power to all new energy stations under the section according to the section power restriction release target; the control module is used to control the new energy station according to the abandoned power and the released power to achieve coordinated control of new energy sections.

[0023] A third aspect of the present invention relates to a terminal, comprising a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method in the first aspect of the present invention.

[0024] The fourth aspect of the present invention relates to a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method in the first aspect of the present invention.

[0025] The beneficial effect of the present invention is that, compared with the prior art, the method and system for coordinated control of a new energy section containing distributed photovoltaics in the present invention optimizes the calculation of the dispatching and control requirements of controllable resources with real-time dispatching characteristics in the entire network or in different regions, and considers the low-voltage distributed photovoltaics as a virtual aggregated control new energy station through aggregation, participating in the global optimization control strategy of the section.

[0026] The beneficial effects of the present invention also include:

[0027] 1. The output of distributed renewable energy is correlated to the distribution of load. By participating in section control, the local balance between distributed renewable energy and load can be achieved, and the utilization efficiency of renewable energy can be improved. Traditional power grid section control mainly considers the output and load requirements of centralized power sources, and has limited capacity to absorb distributed renewable energy. The participation of distributed renewable energy in section control can give full play to its advantages of flexibility and decentralization, and expand the space for absorbing renewable energy.

[0028] 2. It is easy to imagine that the present invention can be combined with existing clustering technology to cluster low-voltage distributed photovoltaics through the similarity of equipment location, grid-connected mode, voltage level, etc., and virtualize multiple new energy sites to participate in section coordinated control and peak-shaving control.

[0029] 3. The present invention fairly distributes the new energy of the entire network to centralized stations and distributed new energy stations according to the section strategy while ensuring the safety of the section, so as to maximize the utilization of the section margin, give full play to the advantages of distributed new energy, fully alleviate the section flow pressure, and reduce the risk of power grid operation.

[0030] 4. The access of distributed new energy can reduce the demand for centralized power sources and long-distance transmission lines, and reduce the cost of grid construction and operation. By participating in section control, distributed new energy can better play its role and further reduce the cost of grid construction and operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of a method for coordinated control of a new energy section including distributed photovoltaics according to the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer and more accurate, the technical solution of the present invention is described in detail below through multiple specific implementation methods. The embodiments adopted by the present invention are only used to explain the present invention and are not used to limit the content of the present invention.

[0033] Figure 1 The figure is a flow chart of a method for coordinated control of a new energy section including distributed photovoltaics according to the present invention. Figure 1 As shown, the first aspect of the present invention relates to a method for coordinated control of a new energy section containing distributed photovoltaics, and the method includes steps 1 to 3.

[0034] Step 1: When the section power flow reaches the first threshold, a section power abandonment target is generated, and the power abandonment amount is allocated to all new energy stations under the section according to the section power abandonment target.

[0035] The present invention calculates the control demand for controllable resources with real-time scheduling characteristics in the entire network or in different regions, and considers the low-voltage distributed photovoltaic as a virtual aggregate control new energy station through aggregation, and participates in the global optimization control strategy of the section. During the control process, power abandonment and power restriction are implemented for a virtual new energy station.

[0036] Preferably, when the section power flow reaches the first threshold, a section power abandonment target is generated, and the power abandonment amount is allocated to all new energy stations under the section according to the section power abandonment target; the section power abandonment target ΔP D for:

[0037] ΔP D =P D -0.9P D.N

[0038] Where P D is the current flow of the section, P D.N is the rated flow of the section;

[0039] The amount of abandoned electricity allocated to any new energy station under the section is:

[0040]

[0041] Where P t.i is the current flow of the new energy station ranked i at time t, and n is the number of new energy stations in the section.

[0042] A transmission section, also known as a power flow section, refers to a bundle of channels composed of several lines or transformers in a larger power grid under certain conditions. The power flow transmission from one area or several nodes with similar electrical distance to another area or several nodes with similar electrical distance is limited. The total amount of power flow transmission does not change significantly when any component in the channel exits, and the components are interrelated when transmitting power flow.

[0043] In actual power systems, system dispatchers often select several lines connecting power centers and load centers as a transmission section based on geographical location. People have not yet made a strict definition of transmission sections. A more standard definition is as follows: Under a certain base state flow, a group of transmission lines with the same active flow direction and similar electrical distance is called a transmission section.

[0044] When there is a need for interconnection between regional power grids A and B and several transmission lines are assumed, a vertical section is cut across the transmission lines. This virtual "surface" can be called a transmission section. The sum of the line flows passing through the transmission section is called the section flow, which is one of the important physical characteristics of the transmission section.

[0045] In order to prevent accidents, a certain transmission margin is reserved and a limit is set for the section to ensure that when the section flow is below this limit, the transmission section has a certain ability to deal with emergencies. This limit is the section limit P. D.N In the present invention, the determining factors of the section limit include the transmission limit of each line of the transmission section, the operation mode of the units in the areas at both ends of the transmission line, the output plan, and the considered accident set.

[0046] When a section reaches 95% of the section value, power is restricted in proportion according to the ranking of all new energy stations in the section. At this time, the unit will no longer implement the multi-source collaborative control strategy until the section flow reaches below 90% of the limit value and maintains the current output control.

[0047] Preferably, when the section power flow reaches the first threshold, a section power abandonment target is generated, and the power abandonment amount is allocated to all new energy stations under the section according to the section power abandonment target, including: if any new energy station in the section fails to respond to the section coordinated control instruction under three consecutive step sizes Δt, the current new energy station is removed from the section, and P is subtracted from the section power abandonment target. t.i , and redistribute the remaining abandoned electricity within the section.

[0048] The power abandonment target of the grid section can be the difference between the sum of the available power generation capacity of each new energy station and the available power generation capacity of the grid.

[0049] Step 2: When the section power flow reaches the second threshold, a section power restriction removal target is generated, and the power restriction removal amount is distributed to all new energy stations under the section according to the section power restriction removal target.

[0050] Preferably, when the section power flow reaches the second threshold, a section power restriction release target is generated, and the power restriction release amount is distributed to all new energy stations under the section according to the section power restriction release target, including:

[0051] Section power restriction removal target ΔP H for:

[0052] ΔP H =0.05P D.N

[0053] The amount of electricity released from restrictions allocated to any new energy station under the section is:

[0054]

[0055] When the section flow drops below 80% of the rated value and lasts for more than 5 minutes, the power restriction operation is executed, and 5% of the rated limit of the section is restored each time. During the recovery process, if the actual output of the wind farm does not reach the power restriction target, the load distribution is transferred, and the transferred power is the power value restored by the station with the later ranking until the power restriction is lifted. During each recovery process, if the section reaches 95% of the rated limit of the section, the control strategy is immediately executed.

[0056] The order in step 1 and step 2 is entered into the system directly after the dispatcher manually sorts the stations. For example, the dispatcher sets the order of station 1, station 2, and station 3 as 3, 2, and 1. Then station 3 is prioritized, followed by station 2, and finally station 1. It can be seen that the dispatch order and dispatch amount are affected by the sorting.

[0057] Preferably, when the section power flow reaches the second threshold, a section power restriction release target is generated, and the power restriction release amount is distributed to all new energy stations under the section according to the section power restriction release target, including: continuously performing power restriction release at each step length Δt, if at time t, the power flow after the power restriction is released at any station meets P t.i <P t-1.i +ΔP H.i , it is considered that the station cannot achieve the target of lifting power restrictions, and at time t+1, it is no longer allocated the target of lifting power restrictions; if at any time t, the power flow after lifting power restrictions at any station meets P t.i ≥P t-1.i +ΔP H.i , it is considered that the station has achieved the target of lifting power restriction, and at time t+1, the target of lifting power restriction will continue to be allocated to it.

[0058] Step 3: Control the new energy station according to the amount of abandoned power and the lifting of power restrictions to achieve coordinated control of new energy sections.

[0059] Preferably, the new energy station is controlled according to the amount of abandoned power and the lifting of power restrictions to achieve coordinated control of new energy sections, including: generating a section power restriction instruction for each new energy station according to the amount of abandoned power and the lifting of power restrictions, and judging whether the section power restriction instruction at the current time t is the last section power restriction instruction; generating a peak-shaving power restriction instruction for each new energy station according to the peak-shaving target of the power grid; and selecting a section power restriction instruction or a peak-shaving power restriction instruction to control the new energy station.

[0060] If it is determined that a certain station cannot reach the target, when calculating again, only the remaining stations will be calculated to restore the target value, and the target value of the station will remain unchanged.

[0061] Among them, selecting the section power restriction instruction or the peak-shaving power restriction instruction to control the new energy station includes: if the peak-shaving power restriction instruction is greater than the section power restriction instruction that is not the last time, the new energy station is deployed in the peak-shaving power restriction mode; if the section power restriction instruction is greater than the peak-shaving power restriction instruction, the new energy station is deployed in the section power restriction mode; if the peak-shaving power restriction instruction is greater than the last section power restriction instruction, the new energy station is deployed in the section power restriction mode. If the peak-shaving power restriction instruction is greater than the last section power restriction instruction, the new energy station is deployed in the peak-shaving power restriction mode after adjusting the state of the new energy station according to the section power restriction instruction.

[0062] The present invention fairly distributes the new energy of the entire network to centralized stations and distributed new energy stations according to the section strategy while ensuring the safety of the section, thereby maximizing the utilization of the section margin, giving full play to the advantages of distributed new energy, fully alleviating the section flow pressure, and reducing the risk of power grid operation.

[0063] The second aspect of the present invention relates to a new energy section coordinated control system containing distributed photovoltaics using the method in the first aspect of the present invention; the system includes a power abandonment module, a power restriction release module, and a control module; wherein the power abandonment module is used to generate a section power abandonment target when the section flow reaches a first threshold, and distribute the abandoned power to all new energy stations under the section according to the section power abandonment target; the power restriction release module is used to generate a section power restriction release target when the section flow reaches a second threshold, and distribute the released power to all new energy stations under the section according to the section power restriction release target; the control module is used to control the new energy stations according to the abandoned power and the released power to achieve coordinated control of new energy sections.

[0064] A third aspect of the present invention relates to a terminal, comprising a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method in the first aspect of the present invention.

[0065] A fourth aspect of the present invention relates to a computer-readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the steps of the method in the first aspect of the present invention.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention is described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention still include contents that can modify or replace the specific embodiments of the present invention. Any modification or replacement that does not depart from the spirit and scope of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A new energy section coordinated control method including distributed photovoltaics, characterized in that: The method comprises the following steps: When the section power flow reaches the first threshold, a section power abandonment target is generated, and the abandoned power is distributed to all new energy stations under the section according to the section power abandonment target; When the section power flow reaches the second threshold, a section power restriction release target is generated, and the power restriction release amount is distributed to all new energy stations under the section according to the section power restriction release target; The new energy station is controlled according to the abandoned power amount and the lifting of power limit to achieve coordinated control of new energy sections.

2. The method for coordinated control of a new energy section containing distributed photovoltaics according to claim 1 is characterized in that: When the section power flow reaches the first threshold, a section power abandonment target is generated, and the abandoned power amount is distributed to all new energy stations under the section according to the section power abandonment target; The section power abandonment target ΔP D for: ΔP D =P D -0.9P D.N Where P D is the current flow of the section, P D.N is the rated flow of the section; The amount of abandoned electricity allocated to any new energy station under the section is: Where P t.i is the current flow of the new energy station ranked i at time t, and n is the number of new energy stations in the section.

3. The method for coordinated control of a new energy section containing distributed photovoltaics according to claim 2 is characterized in that: When the section power flow reaches the first threshold, a section power abandonment target is generated, and the abandoned power amount is distributed to all new energy stations under the section according to the section power abandonment target, including: If any renewable energy station in the section fails to respond to the section coordinated control instruction for three consecutive steps Δt, the current renewable energy station will be removed from the section, and P will be subtracted from the section power abandonment target. t.i , and redistribute the remaining abandoned electricity within the section.

4. The method for coordinated control of a new energy section containing distributed photovoltaics according to claim 3 is characterized in that: When the section power flow reaches the second threshold, a section power restriction release target is generated, and the power restriction release amount is distributed to all new energy stations under the section according to the section power restriction release target, including: The section power restriction target ΔP H for: ΔP H =0.05P D.N The amount of electricity released from the restriction allocated to any new energy station under the section is:

5. The method for coordinated control of a new energy section containing distributed photovoltaics according to claim 4 is characterized in that: When the section power flow reaches the second threshold, a section power restriction release target is generated, and the power restriction release amount is distributed to all new energy stations under the section according to the section power restriction release target, including: The power restriction is continuously lifted at each step length Δt. If at time t, the power flow after the power restriction is lifted at any station meets P t.i <P t-1.i +ΔP H.i , it is considered that the station cannot achieve the target of lifting power restrictions, and at time t+1, no power restriction target will be allocated to it; If at any time t, the power flow after any station is released from power restriction meets P t.i ≥P t-1.i + ΔP H.i , it is considered that the station has achieved the target of lifting power restriction, and at time t+1, the target of lifting power restriction will continue to be allocated to it.

6. A method for coordinated control of new energy sections containing distributed photovoltaics according to claim 5, characterized in that: The controlling the new energy station according to the abandoned power amount and the lifting of power limit to achieve coordinated control of new energy sections includes: Generate a section power restriction instruction for each new energy station according to the abandoned power amount and the lifted power restriction amount, and determine whether the section power restriction instruction at the current time t is the last section power restriction instruction; According to the peak load regulation target of the power grid, a peak load regulation and power restriction instruction is generated for each new energy station; Select section power restriction instruction or peak load power restriction instruction to control new energy stations.

7. A method for coordinated control of new energy sections containing distributed photovoltaics according to claim 6, characterized in that: The selection of section power restriction instructions or peak load restriction instructions to control new energy stations includes: If the peak load-shaving power-limiting instruction is greater than the non-last section power-limiting instruction, the new energy station will be deployed in the peak load-shaving power-limiting mode; If the section power restriction instruction is greater than the peak load power restriction instruction, the new energy station will be deployed in section power restriction mode; If the peak-shaving power-limiting instruction is greater than the last section power-limiting instruction, the status of the new energy station will be adjusted according to the section power-limiting instruction, and the new energy station will be deployed in the peak-shaving power-limiting mode.

8. A new energy section coordinated control system including distributed photovoltaic using the method described in any one of claims 1 to 7; characterized in that: The system includes a power abandonment module, a power restriction release module, and a control module; wherein, The power abandonment module is used to generate a section power abandonment target when the section power flow reaches a first threshold, and distribute the abandoned power to all new energy stations under the section according to the section power abandonment target; The power restriction release module is used to generate a power restriction release target for the section when the section power flow reaches the second threshold, and distribute the power restriction release amount to all new energy stations under the section according to the power restriction release target for the section; The control module is used to control the new energy station according to the abandoned power amount and the lifting of power limit to achieve coordinated control of new energy sections.

9. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1-8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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